1. Field of the Invention
This invention pertains to an oil well blowout containment systems used with a pumping oil well. More specifically, this invention provides a containment system that will prevent oil from polluting the area surrounding the oil well.
2. Description of the Prior Art
There are thousands of oil wells with pumping means to bring the oil to the surface from underground pools. Most of these oil wells have a pump at the bottom of the tubing which lifts a column of oil to the surface.
In the typical oil well pump, a sucker rod which extends down into the well tube is incorporated in the well tube to pump out the oil. The sucker rod is connected to a polished rod which passes through a stuffing box containing one or more packing glands. The polished rod is connected to a bridle which is in turn attached to a horse head on a horse head walking beam with counterweights attached to the other end of the beam. The pumping unit includes a driver motor which imparts the reciprocating motion to the polished rod.
Oil wells that are located close to populated areas present a catastrophic environment problem if the packing gland in the stuffing box fails and the crude oil is disbursed over the surrounding area. In some areas on the West Coast of the United States an oil well operator would be subject to heavy fines if the failed stuffing packing gland resulted in polluting the atmosphere, ground and possibly the water supply.
In other cases the production of the field may be marginal due to the depth of the well or the condition of the producing level. Therefore, many wells are now being injected with steam to increase their productivity. This not only makes the oil less viscous, but it frequently causes the oil to be delivered to the surface under substantial pressure. Now that increased pressures are being generated, the avoidance of bad environmental conditions are an extremely important consideration.
If a packing gland in a stuffing box starts leaking and is not corrected promptly, it may reach excessive levels as the wear by the action of the polished rod increases from continuation of the pumping operation. This excessive wear may also be due to the sand and water sometimes present in the crude oil being pumped. Polished rods, under normal use, will pit and corrode from the various acids present in the crude oil being pumped. In addition, sometimes the production of oil stops due to the well "pumping off" which is defined as the pump becoming gas locked. A gas bubble will occur at the pump at the bottom of the well and work its way to the top to the packing glands. When this happens, the packing in the stuffing box may become damaged due to periods of inadequate lubrication.
Many of the oil wells are dispersed over a wide area and therefore are inspected only occassionally due to the distance involved and the problem of manpower requirements for more frequent observation. If the packing gland in the stuffing box fails in these cases, in addition to the environmental impact, there could be a heavy financial loss, if the failure was not immediately discovered.
What is needed is a device that can contain the crude oil in cases of either a leak or a blowout of the stuffing box packing gland, in addition to providing lubrication to the packing gland at all times. The lubricant in the present invention contains a corrosion inhibitor that will assist in preventing pitting of the polished rod in addition to a lubricating agent that will, under heat and pressure, fill in the microscopic pits and cracks that are normal after any metal surface is machined. This device must also provide means to an inspector that the packing gland has failed and needs replacement.
Prior to this invention, several attempts have been made to contain the oil when a stuffing box packing gland failed. Once such device is described by U.S. Pat. No. 2,915,975 to Kittrell et al. This device measures the leakage past the stuffing box packing gland. Depending on the requirements, the leak rate may be predetermined to shut off the pumping motor and start it again. This does not allow for an inspector to determine the rate of leakage to known when a packing gland should be replaced. In fact, the starting and stopping of an electric motor would be hard on the system and this method would not work for an internal combustion engine at all.
Another device for a leak retriever at the oil well packing gland is given by Smith in U.S. Pat. No. 4,017,214. Smith proposes a complex device that has a small side pump activated by the polished rod reciprocating which pumps the leaked oil back into the discharge line. Again, this device while pumping the oil back into the discharge line, has no means to determine the rate of leakage so that an inspector can determine when the packing gland require replacement.
Another device for leak detection is provided by U.S. Pat. No. 3,180,134 to Wadington. Wadington provides a system very similar to Kitrell except that Wadington provides a pump run by the prime mover to keep a lubricant in the stuffing box between an upper and lower gland under pressure. When the leakage reaches a certain rate, the pressure in the system will drop and activate a switch while will shut down the oil well motor.
Other types of leak containment devices place a bonnet around the stuffing box. These are described in U.S. Pat. No. 3,270,810 to Johnston, U.S. Pat. No. 3,322,198 to McHenry and U.S. Pat. No. 4,665,976 to Retherford.
The novel features which are believed to be characteristics of the invention, both as to its organization and its method of operation, together with further objects and advantages thereof, will be better understood from the following description in connection with the accompanying drawings in which a presently preferred embodiment of the invention is illustrated by way of example. It is expressly understood, however, that the drawings are for purpose of illustration and description only, and are not intended as a definition of the limits of the invention.